The present invention relates to combustion systems for analytical instruments and particularly to a system for cleaning the interior surface of a combustion chamber used therewith.
In combustion systems such as disclosed in U. S. Pat. No. 3,923,464, issued Dec. 2, 1975, to Sitek, et al., and assigned to the present assignee, a quartz tube is employed as a combustion chamber. A specimen in a crucible is positioned within the tube and heated by an induction coil for combusting the specimen. The gases emitted therefrom are subsequently analyzed For determining one or more constituent elements of the specimen. The combustion tube so used is capable of many cycles of operation; however, after each combustion, oxides and other contaminants typically expelled during the combustion process tend to coat the interior of the tube and can, if not removed, interfere with the accuracy of subsequent analyses.
In the past, the combustion tubes have been manually cleaned by an operator brushing them manually with a wire brush. This operation is not only time consuming and tedious but also subjects the combustion tube to breakage during handling and cleaning.
Combustion apparatus of the type described in the above identified patent ans systems such as Model No. CS-46, commercially available from Leco Corporation of St. Joseph, MI, include a filter in the gas flowpath between the source of oxidizing and carrier gas, such as oxygen, and the analyzer for removing particulate material from the combustion gases from a specimen. In the prior art systems above noted, it has been necessary to either replace the filter media or manually remove and clean the screen of the filter. This requirement, together with the requirement of manually cleaning the combustion tube, also leads to additional work for the operator and inconvenience as well as down time of the analyzer.